f(x)=|x(1-x)|(1) x<=-1时f(x)=(-x)(1-x)=-x(1-x)(2) -1f(x)=(-x)(1-x)=-x(1-x)(3) 0f(x)=x(1-x)(4) x>=1时f(x)=x[-(1-x)]=-x(1-x)综上，当0
